It’s not helpful for ACS to publish chemical information that violates the laws of thermodynamics (C&EN, July 15, page 15). On an equal-energy basis, the savings in burning ethanol compared with hydrocarbons such as octane are on the order of 0.8%, not 50%. It absolutely does not create 50% fewer emissions.
What burning ethanol does is recycle the emissions. And if you do not use any fossil fuels in growing, refining, or transporting the wheat starch, you might claim a net reduction in the accumulation of excess CO2, but it will be much less than 50%. The wheat starch used in the bioethanol hopefully is produced and refined within 25 to 50 miles of the new plant and not imported.
Misconceptions about “green energy” do not help the environment. They simply make people feel good and avoid the real issue of looking at the thermodynamic efficiency of the entire energy generation system. Renewable fuels and systems are a positive move in decreasing environmental impact. But let us be scientists and not accept at face value statements that mislead the public.